docs: def best_fts_version():
      "Discovers the most advanced supported SQLite FTS version"
      conn = sqlite3.connect(":memory:")
      for fts in ("FTS5", "FTS4", "FTS3"):
          try:
              conn.execute("CREATE VIRTUAL TABLE v USING {} (t TEXT);".format(fts))
              return fts
          except sqlite3.OperationalError:
              continue
      return None